REPORT FROM THE MERIT PROJECT

Test of Bayesian belief network and stakeholder involvement

Introduction
The applicability of graphical models (Bayesian belief networks – BBNs) in water resource
management regarding preventive groundwater protection was investigated in a case study
for Havelse wellfield catchment in North Zealand. Geological Survey of
Denmark and Greenland (GEUS) was the project leader and Copenhagen Energy (CE) the
decision-maker and end-user in relation to the BBN case study.

CE is the largest water supply company in Denmark. It supplies roughly one million
inhabitants in the greater Copenhagen area with drinking water each day. CE operates
Havelse wellfield together with 55 other large wellfields located in northern and eastern
Zealand (the island on which Copenhagen is located).

Three different types of actions have been analysed as means of protecting water
resources: 1) voluntary farming contracts, 2) afforestation and 3) establishment of
wetlands. For each problem a BBN have been constructed and evaluated with full
stakeholder involvement of both a group of professional stakeholders and a citizens' group.

The possibilities and problems connected with voluntary five-ten-year farmer contracts
prescribing no pesticide application in return for compensational payment was especially
analysed. It was not a question of actually implementing such zones that was in focus in
the study, only analysing what would be required in compensational payment if such zones
were to be implemented at a magnitude and on a scale that allowed them to function as
efficient groundwater protection. Furthermore, the aim was to clarify the impact
implementation of such protection zones could have on land use, farm economics,
groundwater quality, biodiversity and aquatic environment.

Information, consultation and active involvement of professional stakeholders and general
public was carried out using announcements, facilitated public meeting, working group
meetings, newsletters, a Web site, individual meetings and a joint working group. The
facilitator of the public meeting and workshops was the Agenda 21 Centre in
Frederikssund. Various subcontractors have participated in the project, e.g. Svend
Rasmussen (KVL: farm economics) and Jesper Sølver Schou (NERI: value of biodiversity,
land use, etc.).

CHAPTER 6 Development of Bayesian belief networks
(pdf-file, ~3mb)
Hans Jørgen Henriksen
, GEUS
Background
What is a BBN?
An example of a BBN for farming contracts
Methodology of BBN development
BBN for groundwater protection
A BBN for flooding
Validation of BBNs
References